Chapter 1 provides an introduction to the seismic performance of URM buildings and framed buildings with URM infills based on a discussion of their performance during previous EQGMs and of recent research results obtained worldwide. Chapter 2 describes the mechanical properties and dynamic characteristics of an existing RC framed building with URM infills located in the Los Angeles urban area. In Chapter 3, the desirable performances associated with different levels of EQGMs are discussed for framed buildings with URM infills. The seismic performance of the upgraded building is assessed by means of linear and nonlinear analyses. Finally, in Chapter 4 some observations, conclusions and recommendations are presented, with emphasis on the advantages and disadvantages of using PT braces to upgrade existing framed buildings with URM infills. Appendix A describes how the seismic input (corresponding to the safety level EQGM) for the design of the Post-tensioned (PT) braces upgrading scheme was established.